You can see in the below example that I created a store and used that store in a grid. I grabbed a reference to one of the records and passed it to my window component. By default closing a window will destroy it and you can see that the record is not destroyed with the window is closed - if it were it'd remove the row form the grid relating to the record.

If you wanted to destroy the record you'd have to actually do so explicitly - see destroy listener in the example below.